You could dig them out individually, or you could offer them to a garden club or similar group, or you could spray them with a nonselective herbicide containing glyphosate. In many cases where Hostas have been used extensively, there is a reason. For example, the area is shady and full of tree roots and it is therefore difficult to grow grass and other plants, so you may want to make sure this is not the case before you eradicate them. Also, if they are a special collection, there may be some monetary value to the plants and it might be a shame to kill them off outright.